Answer: First, we need to convert the capacity of the fish tank from liters to milliliters since the jug size is given in milliliters.
60 liters = 60,000 milliliters
Next, we need to calculate the volume of water that is already in the tank up to the 4cm mark from the top. Let's assume the tank is a rectangular prism with a length of L, width of W, and height of H. Then, the volume of water up to the 4cm mark can be calculated as:
Volume of water = Length x Width x Height of water level
Volume of water = L x W x (H - 4)
Assuming the tank has a uniform cross-section, we can use the fact that the height of the water level is proportional to the volume of water. That is, if the water level is halfway up the tank, then the volume of water is half the total capacity of the tank.
Let's say the water level is at a height of h from the bottom of the tank. Then, the volume of water in the tank is:
Volume of water = (h / H) x 60,000 mL
We want to solve for h, the height of the water level when it is 4cm from the top. We know that the height of the tank is H, so we can set up a proportion:
(h / H) x 60,000 mL = (H - 4 cm) x L x W
Solving for h, we get:
h = [(H - 4 cm) x L x W x 60,000 mL] / [H x L x W]
h = 59,960 / H
Now, we can calculate the amount of water Lily needs to add to the tank to fill it up to the 4cm mark from the top:
Amount of water needed = 60,000 mL - Volume of water up to 4cm mark
Amount of water needed = 60,000 mL - [(H - 4 cm) x L x W]
We can now calculate the number of jugs of water Lily needs to use by dividing the amount of water needed by the capacity of each jug:
Number of jugs needed = Amount of water needed / 2000 mL
Number of jugs needed = [60,000 mL - (H - 4 cm) x L x W] / 2000 mL
Note that the number of jugs needed will depend on the dimensions of the tank and the height of the water level.
Explanation: